Cryosurgical instrument



United States Patent 1 3,536,075

[72] Inventor Edward R. Thomas, Jr. 3,272,203 9/1966 ChatO l28/303.l Bethesda, Maryland 3,451,395 6/ 1969 Thybel'g 128/3031 [21] Appl. No. 657,614 3,289,424 12/1966 Shepherd... 128/3031 [22] Filed Aug. 1, 1967 3,369,549 2/1968 Armao 128/303.1 [45] Patented Oct. 27, 1970 3,393,679 7/1968 Crump et a1. 128/303.1 [73] Assignee Northwestern University 3,398,738 8/1968 Lamb et a1 l28/303.1

Evanston mmols Primary ExaminerAnton O. Oechsle W Assistant Examiner-Richard J. Apley 54 CRYOSURGICAL UMENT Attorney-Marechal, Biebel, French & Bugg 14 Claims, 8 Drawing Figs.

[ 128/301l ABSTRACT: An instrument system for performing surgery [5 Int. using very old tem eratures includes a penciblike in- [50] Field of Search 128/303, Strumem adapted to have a li fi d gas evaporated near the 303-1, 4O0402 tip of a probe to reduce substantially the temperature thereof. In order to increase the cooling effect, a vacuum is a lied to [56] References cued the exhaust to increase the rate of evaporation. In iie em- UNITED STATES PATENTS bodiment, the liquefied gas in the liquid state is used to raise 2,645,097 7/1953 Posch 128/400X the temperature of the probe, and the entire operation of the 2,672,032 3/1954 Towse..... 2,982,112 5/1961 Keyes 128/3011 instrument is controlled from a single manual valve which may 1 28/ 303. 1X be mounted on the instrument or be a foot pedal.

d e J a. e f a fi F 4O\. U 52 4:

Patented Oct. 27, 1970 3,536,075

INVENTOR EDWARD R. THOMAS, JR.

ATTORNEYS CRYOSURGICAL INSTRUMENT RELATED APPLICATIONS Reference is made to my copending applications Ser. No. 447,124, filed April 12, [965 and now U.S. Pat. No. 3,439,680 and Ser. No. 596,705, filed November 23, 1966 and now US. Pat. No. 3,434,477, both assigned to the assignee of this application.

BACKGROUND OF THE INVENTION Very cold temperatures have come into acceptance for many surgical operations and treatment, both on humans and animals. For example, cryosurgery is being used for treating brain tumors, for removing cataracts from the eyes, as well as for repairing detached retinas. Much of the equipment designed heretofore has been very complex, bulky and heavy. It is dIfiICUII for the surgeon to master the operation of the apparatus without complete understanding of the technical details thereof, thus impeding the acceptance of these instruments. The hand piece utilized to apply the cold temperatures frequently has a large diameter in order to provide the proper insulation so that the cold temperatures are not transmitted to the surgeons hand, and this makes the instrument difficult to maneuver during surgery.

Accordingly, there is a substantial need for an instrument of very simplified design which can be easily transported by the surgeon and which provides a maximum amount of cooling at the end of the probe. Moreover, it is desirable that these devices have means for heating the probe in order to raise the temperature thereof as required during the surgery.

SUMMARY OF THE INVENTION A cryosurgical system having a pencil-like hand piece which supplies liquid gas through a very small tube which sprays it adjacent the tip, and having an exhaust system connected to a vacuum pump so that the gas is quickly evaporated and removed from the probe. This permits maximum heat to be extracted through the tip to insure that no prolonged contact with a portion of the human body cannot increase the temperature of the tip. When desired, the temperature of the tip can be elevated by flooding the probe with the liquid gas which is still a relatively low temperature but warmer than the temperature produced by the evaporating liquid. In one embodiment, the flow of liquid gas is controlled from a foot switch while in another it is controlled from a small valve in the pencil-like hand piece. In a third embodiment. a U-shaped probe is utilized and no valve is provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional view taken centrally through a preferred embodiment of the invention and showing the associated controls schematically; I

FIG. 2 is a sectional view similar to FIG. I showing another embodiment of the invention;

FIG. 3 is a sectional view of the valve showing it in its alternate position and taken along the line 3-3 of FIG. 4;

FIG. 4 is another sectional view taken along the line 44 of FIG. 6;

FIG. 5 is a plan view of the probe utilized in the instrument shown in FIG. 2;

FIG. 6 is a plan view of the valve actuator;

FIG. 7 is a sectional view similar to FIG. 1 showing another embodiment of the invention; and

FIG. 8 is an enlarged view partially broken away and illustrating the U-shaped probe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The surgical apparatus shown in FIG. 1 includes a pencillike instrument 10 which can be held in the hand of a surgeon in substantially the same manneer as a pen or pencil. The instrument 10 includes an elongated hand piece 11 of a plastic passage 12 has an elongated restricted passage 21 which connects centrally with this bore, and the exhaust passage 14 has a shorter restricted passage 22 in communication with the bore.

The probe 25 is removably secured in the left-hand end of the hand piece 11, as shown in FIG. 1, and includes a frustoconical body 26 having the closed outer tube 27 secured in the central bore 28 and extending to the curved end portion 30 thereof with the tip 31 on the end thereof. The other end of the tube 27 extends beyond the body 26 and has the threaded bushing 32 thereon adapted to threadedly engage the bore 16 to secure the probe on the hand piece 11. The O-ring seal 33 in the annular groove in the end surface 34 of the hand piece 11 seals against the body 26 and prohibits the escape of gas or liquids therebetween.

A small diameter tube 35 is supported within the outer tube 27 by the brackets 36, and the right-hand end thereof extends beyond the outer tube 27 so that it is received in the left-hand end of the restricted passage 21. The O-ring seal 37 in the hand piece adjacent the end of the passage 21 seals against the end of the tube 35 so that the liquid flows from the passage 21 directly into the needle-like tube 35 which conducts it to its outlet 38 adjacent the tip 31. A plastic cover insulator 39 may be provided around the outer tube 27 of the probe to prohibit the escape of heat through this outer tube except in the area of the tip 31.

The refrigerant control system for the surgical instrument includes a source of liquid gas. for example, liquid nitrogen, in the form of a cylinder 40 having a manual valve 42 thereon. This cylinder is connected by the conduit 43 having the filter 44 therein to a three-way valve 45 which is operated by a foot pedal 46 and the spring 47. The valve 45 is connected to the inlet and bypass passages 12 and 13 in the hand piece 11 by the flexible conduits 48 and 49. In addition, the valve is connected to a vacuum pump 50 through the flexible conduit 51 having the one-way check valve 52 therein, and this pump is also connected to the vent passage 14 in the hand piece 11 through the flexible conduit 53. Each of the conduits 48, 49 and 53 is connected to the hand piece 11 by a suitable coupling 55 which may be permanent or detachable without departing from the scope of the invention.

The operation of the valve will now be described in connection with the operation of the entire instrument system. Accordingly, the instrument 10 is ready for use when the various conduits are properly attached, the cylinder 40 of refrigerant is connected to the conduit 43 and the valve 42 opened, and the source of power for the vacuum pump 50 is connected thereto. The spring 47 normally positions the valve 45 in the Off position (FIG. 1) wherein flow of refrigerant from the conduit 43 is blocked and not permitted into the conduits 48, 49 or 51.

When it is desirable to reduce the temperature of the tip 31 to perform the surgical operation, the surgeon depresses the foot pedal 46 so that the valve passage 57 interconnects the conduits 43 and 48 thereby feeding the liquid gas into the inlet passage 12 and into the needle-like tube 35 which conducts the liquid gas to a position adjacent the tip 31. The gas is then sprayed from the end of this tube and, because the vacuum pump 50 is applying a suction through the conduit 53 and the exhaust passage 14, the liquid is quickly evaporated and withdrawn from the space 58 around the outside of the inner tube 36. There is little or no unevaporated liquid in this space because of the quick removal thereof, so that the tip 31 is quickly cooled and remains cooled even when placed in contact with a heated portion of the body.

when it is desirable to raise the temperature of the tip 31 from this very cold temperature, the surgeon merely depresses the valve 45 to align the valve passages 61 and 62 with the conduits 4349 and 48-51 so that the liquid refrigerant flows through the conduits 43 and 49 and into the bypass passage 13, and into the space at the right end of the tube 27 and the space 58 around the needle-like tube 35. Because of the restricted passage 22 in the exhaust passage 14 and the pressurization of the liquid, the entire space 58 is quickly filled with liquid so that the temperature of the tip is raised to the temperature of the liquid gas, which may be cold but always much warmer than temperature present during evaporation of the gas. The restricted passage 22 prohibits the gas from being drawn directly into the exhaust passage 14 although the vacuum continues at all times to remove a portion of this liquid which will be at least partially evaporated. The exhaust gas, whether liquid or gas, is then drawn through the conduit 48, the valve passage 62, and the conduit 51 having the check valve 52 therein.

If the surgeon again requires a low temperature at the tip 31, he merely removes pressure from the foot pedal 46 and allows the spring 47 to return the valve 45 to the position wherein the valve passage 57 again connects the conduits 43 and 49 at which time the operation described above is recommenced. The vacuum is sufficient to evacuate quickly the space 58 once the supply through the passage 13 is terminated. When the surgeon is finished with the instrument, the spring 47 returns the valve to the Off position wherein the conduits 48, 49, and 51 are blocked and further flow of refrigerant is not permitted. However, the vacuum continues to withdraw all of the refrigerant of the instrument through the exhaust passage 14.

Another embodiment of the invention is shown in HQ 2 which also includes a pencil-like hand piece 11a which also can be easily held in the hand of a surgeon. This hand piece includes an elongated body of plastic material having parallel inlet and exhaust passages 70 and 71 therein. in the restricted portion 72 of the passage 70 a small valve 73 is provided for diverting the flow of liquid into a bypass passage 74 formed in the hand piece 110, and leading to a complementary passage 76 in the body 77 of the probe assembly 78.

As shown in FIGS. 3 and 4, the valve 73 includes a cylindrical body 81 mounted in a complementary bore 82 in the hand piece 11a and held therein by the annular retainer 83 which surrounds the upstanding stem 84 on the body 81 and engages the complementary threads 85 on the outer end of the bore. A suitable washer 86 is provided between the shoulder 87 on the body of the retainer for frictionless rotation of the latter. The O-ring seals 89 are interposed between the body 81 and the hand piece 11a to block the escape of gas or liquids therefrom.

A passageway 88 is provided centrally through the body adapted to communicate with the opposite ends 90 and 91 of the restricted passage 72. The right-hand end 93 of this valve passage 88 is is enlarged so that it remains in communication with the right-hand end 90 of the passage 72 as the valve 73 is rotated to a position wherein the left-hand end is in communication with the bypass passage 74, as shown in FIG. 3. A suitable knob 95 is provided on the stem 84 for turning the valve 73 between an Off positon wherein the passage 88 is not aligned with either of the passage 72 or 74, the straight through position as shown in FIG. 2 wherein the valve passage 88 connects the passages 70 and 72, and the bypass position as shown in FIG. 3 wherein it connects the passages 70 and 74. A pointer 96 is provided on the knob 95 for indicating the position of the valve 73.

The probe assembly 78 in this embodiment includes the elongated outer tube 97 having a circular shaped tip 98 on the end thereof, as shown in FIG. 5. The outer tube 97 and the tip 98 are hollow and the needle-like inner tube 100 extends through the outer tube and approximately one-half way around the circular tip 98. This inner tube is held in the outer tube 97 by the brackets 99, and is adapted to engage the restricted passage in the same manner as described above in connection with FIG. 1. Similarly, the probe assembly 78 is secured to the left-hand end of the hand piece 11a in the same manner as described above.

The bypass passages 74 and 76 in the hand piece and the body 77 of the probe assembly communicate through a tube 101 to a point in the hollow circular tip 98 opposite the juncture 102 with the outer tube 97 so that flow from the passages 74 and 76 enters the interior space 103 of the tip 98 at the farthest point from the aforesaid juncture 102. A tank 40a of liquid gas is connected to the inlet passage 70 through the flexible conduit 104 having the filter 440 therein, whereas the exhaust passage 71 is connected by the flexible conduit 106 to the vacuum pump 50a which may be of any conventional design. 1

In operation of this embodiment, after the tai'ilctgfla of refrigerant and the vacuum pump 50a are connected to the hand piece 11a by the conduits 104 and 106, the valve 42a of the tank 40a is opened so that the pressure therein forces liquid refrigerant into the inlet passage 70 in the hand piece. The surgeon will have moved the valve 73 to the closed position so that the body 81 blocks the restricted passage 72 and the refrigerant will flow no further than the valve. When it is desired to cool the circular tip 98 of the probe assembly 78, the valve 73 is moved to the open position wherein the refrigerant flows through the valve passage 88, the restricted passage 72, and into the needle-like tube from where it is sprayed into the space 103 in the interior of the annular tip 98 to reduce the temperature thereof. The evaporation is very fast and efficient due to the vacuum being applied to the exhaust passage 71 in the space by the vacuum pump 50, as described above. The gases quickly evaporate and are withdrawn through the passage 71.

When it is desirable to quickly raise the temperature of the tip 98, the surgeon moves the knob 95 to the bypass position wherein the liquid refrigerant flows through the valve passage 88 and into the bypass passages 74 and 76, through the tube 101, and into the space 103 in the interior of the annular tip 98 and the outer tube 97. Since the liquid floods the tip, no evaporation occurs, and the tip 98 is raised to the temperature of the liquid which is much warmer than that created by the evaporation of the liquid. The vacuum continues to withdraw the liquid and any gas which may be created into the vent passage 71 through the restricted passage 22 which limits the rate of withdrawal so that the flooding can take place. When the valve 73 is moved to the open position again, the tip is again cooled as the vacuum draws the flooded refrigerant therefrom. Moreover, if the valve 73 is turned to the Off position the vacuum will continue to exhaust all refrigerant from the bypass system.

Another embodiment of the invention is shown in FIGS. 7 and 8, including the hand piece 11b having parallel inlet and vent passages and 121 therein. The probe 123 has its body 124 threadedly secured in the recessed end 125 of the hand piece 11b and the O-ring seal 126 insures that the refrigerant will not escape through the threaded connection. The tip 127 includes an elongated U-shaped outer tube 128 which communicates with the passage 130 and 131 in the body of the probe which in turn are aligned with the inlet and vent passages 120 and 121. The needle-like inner tube 132 is mounted in the passage 130 for conducting the liquid refrigerant to the end portion 134 of the tip. As shown in FIG. 8. the end portion of the tip is filled with a porous plastic material 135 having maximum amount of surface area, such as Zitex, which insures that the liquid will be spread over the surfaces thereof and quickly evaporated.

In operation, the tank 40b of refrigerant is connected to the inlet passage through the flexible conduit 137 and the filter 44b, and when the valve 41b on the tank is opened, the refrigerant flows through the inlet passage 120, and into the inner tube 132 and then is sprayed from the end thereof into the end portion 134 of the tip. Much of the evaporation occurs as the refrigerant is sprayed from the tube 132, but any remaining liquid quickly spreads on the surfaces of the porous material 135 and the movement of gas flowing thereover effects rapid evaporation thereof. The evaporation is facilitated by the vacuum which it continually draws the gases from the passages and vents them to the atmosphere.

Accordingly, the invention has provided an improved cryosurgical system wherein a pencil-like instrument which is easy to manipulate by the surgeon has the efficiency of evaporation greatly increased by applying a vacuum to withdraw the evaporated gases from the instrument. In this way there is no back pressure but rather a continual flow of gas from the instrument for maximum evaporation and cooling at the tip so that a much smaller instrument can absorb and increase the amount of heat passing through the tip. In addition, the invention provides for the flooding of liquid into the tip to warm quickly the tip when required by the surgeon. This flooding can be accomplished by a foot valve or a valve mounted directly on the hand piece of the instrument. The precise temperature created during operation of the invention is dependent upon the gases used, and the selection of the gases can be made by one skilled in the art.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

I claim:

1. A surgical instrument for use in producing very cold temperatures comprising, a pencil-like hand piece having parallel inlet and outlet passages extending longitudinally therethrough, means defining a restriction in the downstream end of said inlet passage, an elongated hollow probe releasably secured in a fluid-tight manner to the said downstream end of said hand piece in alignment with said restriction, a small diameter tube having one end in communication with said restriction for receiving the flow of liquid therefrom, said tube extending axially into said hollow probe and having its other end terminating adjacent the tip of said probe so that the liquid gas flowing from said tube is sprayed into the space adjacent said tip wherein it boils to reduce the temperature of said tip to a preset low temperature, an exhaust passage defined between the outside of said tube and the inside of said probe for flow of evaporation of liquid from said space. means in said hand piece connecting said exhaust passage with said outlet passage so that gases are expelled from said probe through said hand piece, means for connecting said inlet passage to a source of liquid gas under pressure, and vacuum means connected to said exhaust passage for withdrawing evaporated gases therefrom to increase the rate of evaporation and extract more heat through said tip to maintain said tip at a preset low temperature.

2. A surgical instrument as defined in claim 1 comprising bypass means for flooding liquid gas into said tip to raise the temperature thereof above said preset low temperature.

3. A surgical instrument as defined in claim 2 wherein said bypass means includes a bypass passage extending through said hand piece parallel to said inlet and outlet passages, said bypass passage communicating with said space adjacent said tip, and valve means for controlling the flow of liquid gas to said inlet and bypass passages.

4. A surgical instrument as defined in claim 3 wherein said valve means is a manually operable valve adapted to connect the source of liquid gas to either said inlet or bypass passages.

5. A surgical instrument as defined in claim 3 wherein restriction means are provided in said exhaust conduit so that said liquid gas floods said space prior to being withdrawn through said exhaust conduit by said vacuum means.

6. A surgical instrument as defined in claim 4 wherein said inlet passage is connected to said vacuum means when said source is connected to said bypass passage.

7. A surgical instrument as defined in claim 3 wherein said valve means is mounted in said pencil-like hand piece and adapted to control the flow throu h said inlet passa e.

8. A surgical instrument as de med m claim 3 w erem said valve means is a small plug valve mounted in said pencil-like hand piece and adapted to control the flow through said inlet and bypass passages.

9. A surgical instrument as defined in claim 3 wherein said valve means is a foot operated switch adapted to control the flow through said inlet passage.

10. A surgical instrument as defined in claim 1 wherein said valve means is a foot operated valve disposed remote from said hand piece and adapted to control the flow through said inlet and bypass passages, said valve also connecting said inlet passage to said vacuum means when said source is connected to said bypass passage.

11. A surgical instrument as defined in claim 3 wherein said valve means includes a cylindrical plug mounted in a bore extending radially into said hand piece, retainer means adapted to maintain said plug in said bore, said bore extending through said inlet passage, a valve passage adapted to block said inlet passage, and manual means for rotating said plug.

12. A surgical instrument as defined in claim 1 wherein said hollow probe is U-shaped.

13. A surgical instrument as defined in claim 12 wherein said small tube extends through the inlet side of said U-shaped probe to a position adjacent the loop thereof, said loop being filled with a highly porous material adapted to subject the liquid to maximum surface area for increasing expansion thereof.

14. A surgical instrument as defined in claim 3 wherein said probe includes an outer tube having a circular tip on the end thereof, said bypass passage being connected to said circular tip at a point remote from the juncture between said outer tube and said tip for flooding said tip to increase the temperature thereof. 

